Change of the main parameters of 24-hour ekg monitoring in patients with myocardial infarction associated with ventricular arrhythmias

Abstract

Aim. To study the change of the main parameters of 24-hour EKG monitoring over time in patients with myocardial infarction associated with ventricular arrhythmias of different grades. Methods. The change of the echocardiography parameters, heart rhythm variability, corrected QT interval duration and dispersion, late ventricular potentials, heart rhythm turbulence were examined in 70 adult men (mean age 52.6±1.3 years) with primary Q-wave myocardial infarction on 10-14th day of the disease and after 6 months. Patients were assigned into 3 groups depending on ventricular arrhythmias severity (according to Lown classification modified by Ryan): А1 (n=29) - grade 1-2, А2 (n=23) - grade 3-4, А3 (n=18) - patients with paroxysmal ventricular tachycardia. Results. Presence of late ventricular potentials and pathologic heart rhythm turbulence in patients in acute period of myocardial infarction suggested high grade of ventricular arrhythmia. Ventricular arrhythmias were associated with severe sympathicotonia, prolongation of corrected QT interval and QT dispersion. 6 months after Q-wave myocardial infarction an autonomic imbalance increased and no positive changes of myocardial homogenicity parameters, late ventricular potentials and pathologic heart rhythm turbulence were observed with increasing ventricular arrhythmia grading and heart rate frequency. A relationship between left ventricle ejection fraction, myocardium mass and myocardial electric non-stability values was revealed. In patients with Q-wave myocardial infarction ventricular arrhythmias are mediated by several mechanisms: systolic and autonomic disorder, repolarization abnormalities, late ventricular potentials pathologic heart rhythm turbulence. The severity of abnormalities is marked by the ventricular arrhythmias grade. Conclusion. 6 months after myocardial infarction (in healing stage) the significant positive changes are found only in patients with 1-2 grades ventricular arrhythmias. The significant non-homogeneity of myocardial electrophysiological features still persists in patients with life-threatening ventricular arrhythmias.

Keywords

Q-wave myocardial infarction / heart rhythm variability / repolarization abnormalities / late potentials / rhythm turbulence / echocardiography / electrocardiography

RIGHTS & PERMISSIONS

Logacheva I.V., Barantseva N.G.